Note: Descriptions are shown in the official language in which they were submitted.
CA 02977629 2017-08-23
DESCRIPTION
PARITY PUNCTURING DEVICE FOR VARIABLE-LENGTH
SIGNALING INFORMATION ENCODING AND PARITY
PUNCTURING METHOD USING SAME
Technical Field
100011 The present invention relates to channel encoding and modulation
techniques for the transmission of signaling information, and more
particularly to
encoding and decoding apparatuses for effectively transmitting signaling
information in
a next generation digital broadcasting system.
Background Art
[0002] Bit-Interleaved Coded Modulation (BICM) is bandwidth-efficient
transmission technology, and is implemented in such a manner that an error-
correction
coder, a bit-by-bit interleaver and a high-order modulator are combined with
one
another.
[0003] BICM can provide excellent performance using a simple structure
because
it uses a low-density parity check (LDPC) coder or a Turbo coder as the error-
correction
coder. Furthermore, BICM can provide high-level flexibility because it can
select
modulation order and the length and code rate of an error correction code in
various
forms. Due to these advantages, BICM has been used in broadcasting standards,
such
as DVB-T2 and DVB-NGH, and has a strong possibility of being used in other
next-
generation broadcasting systems.
[0004] Such BICM may be used not only for the transmission of data but also
for
the transmission of signaling information. In particular, channel encoding and
modulation techniques for the transmission of signaling information need to be
more
robust than channel encoding and modulation techniques for the transmission of
data.
[0005] Therefore, in particular, there is a pressing need for new channel
encoding
and modulation techniques for the transmission of signaling information.
Disclosure
Technical Problem
CA 02977629 2017-08-23
a
[0006] An object of the present invention is to provide channel
encoding and
modulation techniques that are appropriate for the transmission of signaling
information
via a broadcast system channel.
[0007] Another object of the present invention is to provide a new
parity
puncturing technique that is optimized for the transmission of signaling
information.
Technical Solution
[0008] In order to accomplish the above objects, the present
invention provides a
parity puncturing apparatus, including: memory configured to provide a parity
bit string
for parity puncturing for the parity bits of an LDPC codeword whose length is
16200 and
whose code rate is 3/15; and a processor configured to puncture a number of
bits
corresponding to a final puncturing size from the rear side of the parity bit
string.
[0009] In this case, the LDPC codeword may include zero-padded
variable length
signaling information as information bits.
[0010] In this case, the final puncturing size may be calculated
using a temporary
puncturing size, the number of transmission bits and the temporary number of
transmission bits, the number of transmission bits may be calculated using the
temporary
number of transmission bits and a modulation order, the temporary number of
transmission bits may be calculated using the difference between the sum of
the length of
a BCH-encoded bit string and 12960, and the temporary puncturing size, and the
temporary puncturing size may be calculated using a value obtained by dividing
the
difference between the length of an LDPC information bit string and the length
of the
BCII-encoded bit string by 2.
[0011] In this case, the temporary puncturing size may be calculated
using a first
integer, multiplied by a value obtained by dividing the difference between the
length of
the LDPC information bit string and the length of the BCH-encoded bit string
by 2, and a
second integer different from the first integer.
[0012] In this case, the first integer may be 7, and the second
integer may be 0.
In this case, the modulation order may be 2 that corresponds to QPSK.
[0013] In this case, the parity bit string may be generated by
segmenting the parity
bits of the LDPC codeword into a plurality of groups and then group-wise
interleaving the
groups using an order of group-wise interleaving.
[0014] In this case, the order of group-wise interleaving may
correspond to a
sequence [16 22 27 30 37 44 20 23 25 32 38 41 9 10 17 18 21 33 35 14 28 12 15
19 11 24
29 34 36 13 40 43 31 26 39 42].
2
CA 02977629 2017-08-23
[0015] Furthermore, according to an embodiment of the present invention,
there is
provided a parity puncturing method, including: calculating a temporary
puncturing size
using the difference between the length of an LDPC information bit string and
the length
of a BCH-encoded bit string; calculating the temporary number of transmission
bits using
the difference between the sum of the length of the BCH-encoded bit string and
12960 and
the temporary puncturing size; calculating the number of transmission bits
using the
temporary number of transmission bits and a modulation order; calculating a
final
puncturing size using the temporary number of transmission bits, the number of
transmission bits, and the temporary number of transmission bits; and
puncturing the
number of bits corresponding to the final puncturing size from the rear side
of a parity bit
string for parity puncturing for the parity bits of an LDPC codeword whose
length is
16200 and whose code rate is 3/15.
[0016] In this case, the LDPC codeword may include zero-padded variable
length
signaling information as information bits.
[0017] In this case, the temporary puncturing size may be calculated using
a value
obtained by dividing the difference between the length of the LDPC information
bit string
and the length of the BCH-encoded bit string by 2.
[0018] In this case, the temporary puncturing size may be calculated using
a first
integer, multiplied by a value obtained by dividing the difference between the
length of
the LDPC information bit string and the length of the BCH-encoded bit string
by 2, and a
second integer different from the first integer.
[0019] In this case, the first integer may be 7, and the second integer may
be 0.
In this case, the modulation order may be 2 that corresponds to QPSK.
[0020] In this case, the parity bit string may be generated by segmenting
the parity
bits of the LDPC codeword into a plurality of groups and then group-wise
interleaving the
groups using an order of group-wise interleaving.
[0021] In this case, the order of group-wise interleaving may correspond to
a
sequence [16 22 27 30 37 44 20 23 25 32 38 41 9 10 17 18 21 33 35 14 28 12 15
19 11 24
29 34 36 13 40 43 31 26 39 42].
[0022] Furthermore, according to an embodiment of the present invention,
there is
provided an inverse parity puncturing apparatus, including: a process
configured to
calculate a temporary puncturing size using the difference between the length
of an LDPC
information bit string and the length of a BCH-encoded bit string, to
calculate the
temporary number of transmission bits using the difference between the sum of
the length
of the BCH-encoded bit string and 12960, and the temporary puncturing size, to
calculate
3
84066564
the number of transmission bits using the temporary number of transmission
bits and a
modulation order, to calculate a final puncturing size using the temporary
number of
transmission bits, the number of transmission bits and the temporary number of
transmission
bits, and to perform inverse puncturing corresponding to the final puncturing
size, thereby
generating a parity bit string of an LDPC codeword whose length is 16200 and
whose code
rate is 3/15; and memory configured to store the parity bit string.
[0023] In this case, the LDPC codeword may include zero-padded variable
length
signaling information as information bits.
[0024] In this case, the temporary puncturing size may be calculated using
a value
obtained by dividing the difference between the length of the LDPC information
bit string and
the length of the BCH-encoded bit string by 2.
[0025] In this case, the temporary puncturing size may be calculated using
a first
integer, multiplied by a value obtained by dividing the difference between the
length of the
LDPC information bit string and the length of the BCH-encoded bit string by 2,
and a second
integer different from the first integer.
[0026] In this case, the first integer may be 7, and the second integer may
be 0. In
this case, the modulation order may be 2 that corresponds to QPSK.
[0026a] According to an embodiment, there is provided a parity puncturing
apparatus,
comprising: memory configured to provide a parity bit string for parity
puncturing for parity
bits of an LDPC codeword whose length is 16200 and whose code rate is 3/15;
and a
processor configured to puncture a number of bits corresponding to a final
puncturing size
on a rear side of the parity bit string, wherein the parity bit string is
generated by segmenting
the parity bits of the LDPC codeword into a plurality of groups and then group-
wise
interleaving the groups using an order of group-wise interleaving, wherein the
final
puncturing size is calculated using a temporary puncturing size, a number of
transmission
bits, and a temporary number of transmission bits; the number of transmission
bits is
calculated using the temporary number of transmission bits and a modulation
order; the
temporary number of transmission bits is calculated using a difference between
a sum of a
length of a BCH-encoded bit string and 12960, and the temporary puncturing
size; and the
temporary puncturing size is calculated using a value obtained by dividing a
difference
between a length of an LDPC information bit string and the length of the BCH-
encoded bit
4
CA 2977629 2018-12-19
84066564
string by 2, wherein the temporary puncturing size is calculated using a first
integer,
multiplied by the value obtained by dividing the difference between the length
of the LDPC
information bit string and the length of the BCH-encoded bit string by 2, and
a second
integer different from the first integer, wherein the first integer is 7, and
the second integer
is 0 and the modulation order is 2 that corresponds to QPSK.
[0026b] According to another embodiment, there is provided a parity
puncturing
method, comprising: calculating a temporary puncturing size using a difference
between a
length of an LDPC information bit string and a length of a BCH-encoded bit
string;
calculating a temporary number of transmission bits using a difference between
a sum of the
length of the BCH-encoded bit string and 12960, and the temporary puncturing
size;
calculating a number of transmission bits using the temporary number of
transmission bits
and a modulation order; calculating a final puncturing size using the
temporary puncturing
size, the number of transmission bits, and the temporary number of
transmission bits; and
puncturing a number of bits corresponding to the final puncturing size on a
rear side of a
parity bit string for parity puncturing for parity bits of an LDPC codeword
whose length is
16200 and whose code rate is 3/15, wherein the parity bit string is generated
by segmenting
the parity bits of the LDPC codeword into a plurality of groups and then group-
wise
interleaving the groups using an order of group-wise interleaving, wherein the
temporary
puncturing size is calculated using a value obtained by dividing a difference
between the
length of the LDPC information bit string and the length of the BCH-encoded
bit string
by 2, wherein the temporary puncturing size is calculated using a first
integer, multiplied by
a value obtained by dividing a difference between the length of the LDPC
information bit
string and the length of the BCH-encoded bit string by 2, and a second integer
different
from the first integer, wherein the first integer is 7, and the second integer
is 0 and the
modulation order is 2 that corresponds to QPSK.
10026c1 According to another embodiment, there is provided an inverse
parity
puncturing apparatus, comprising: a process configured to calculate a
temporary puncturing
size using a difference between a length of an LDPC information bit string and
a length of a
BCH-encoded bit string, to calculate a temporary number of transmission bits
using a
difference between a sum of the length of the BCH-encoded bit string and 12960
and the
temporary puncturing size, to calculate a number of transmission bits using
the temporary
4a
CA 2977629 2018-12-19
84066564
number of transmission bits and a modulation order, to calculate a final
puncturing size
using the temporary puncturing size, the number of transmission bits, and the
temporary
number of transmission bits, and to perform de-puncturing corresponding to the
final
puncturing size, thereby generating parity values corresponding to parity bits
of an LDPC
codeword whose length is 16200 and whose code rate is 3/15; and memory
configured to
store the parity values, wherein the parity values are used for group-wise de-
interleaving
after the de-puncturing, wherein the temporary puncturing size is calculated
using a value
obtained by dividing a difference between the length of the LDPC information
bit string and
the length of the BCI-I-encoded bit string by 2, wherein the temporary
puncturing size is
calculated using a first integer, multiplied by a value obtained by dividing a
difference
between the length of the LDPC information bit string and the length of the
BCH-encoded
bit string by 2, and a second integer different from the first integer,
wherein the first integer
is 7, and the second integer is 0 and the modulation order is 2 that
corresponds to QPSK.
Advantageous Effects
[0027] According to the present invention, the channel encoding and
modulation
techniques that are appropriate for the transmission of signaling information
via a broadcast
system channel are provided.
[0028] Furthermore, in the present invention, shortening and puncturing are
optimized according to the amount of signaling information in the construction
of BICM for
the transmission of signaling information, thereby being able to efficiently
transmit/receive
the signaling information.
Description of Drawings
[0029] FIG. 1 is a block diagram showing a signaling information
encoding/decoding
system according to an embodiment of the present invention;
[0030] FIG. 2 is an operation flowchart showing a signaling information
encoding
method according to an embodiment of the present invention;
[0031] FIG. 3 is an operation flowchart showing a signaling information
decoding
method according to an embodiment of the present invention;
4b
CA 2977629 2018-12-19
CA 02977629 2017-08-23
[0032] FIG. 4 is a diagram showing a broadcast signal frame according to an
embodiment of the present invention;
[0033] FIG. 5 is a diagram showing the structure of a parity check matrix
(PCM)
corresponding to an LDPC code according to an embodiment of the present
invention;
[0034] FIG. 6 is a diagram showing an example of the operation of the zero
padding unit shown in FIG. 1;
[0035] FIG. 7 is a diagram showing an example of the operation of the
parity
permutation unit shown in FIG. 1;
[0036] FIG. 8 is a diagram showing an example of the operation of the zero
removing unit shown in FIG. 1;
[0037] FIG. 9 is a block diagram showing a parity puncturing apparatus
according to an embodiment of the present invention; and
[0038] FIG. 10 is an operation flowchart showing a parity puncturing method
according to an embodiment of the present invention.
Mode for Invention
[0039] The present invention will be described in detail below with
reference to
the accompanying drawings. Repeated descriptions and descriptions of well-
known
functions and configurations that have been deemed to make the gist of the
present
invention unnecessarily obscure will be omitted below. The embodiments of the
present invention are intended to fully describe the present invention to
persons having
ordinary knowledge in the art to which the present invention pertains.
Accordingly, the
shapes, sizes, etc. of components in the drawings may be exaggerated to make
the
description obvious.
[0040] Preferred embodiments of the present invention will be described in
detail
below with reference to the accompanying drawings.
[0041] FIG. 1 is a block diagram showing a signaling information
encoding/decoding system according to an embodiment of the present invention.
[0042] Referring to FIG. 1, the signaling information encoding/decoding
system
includes a signaling information encoding apparatus 100, and a signaling
information
decoding apparatus 300.
[0043] The signaling information encoding apparatus 100 and the signaling
information decoding apparatus 300 perform communication through the medium of
a
wireless channel 200.
CA 02977629 2017-08-23
[0044] The signaling information encoding apparatus 100 channel-encodes and
modulates signaling information, such as Li-Basic, Li-Detail or the like.
[0045] The signaling information encoding apparatus 100 includes a
segmentation unit 110, a scrambling unit 120, a BCH encoder 130, a zero
padding unit
140, an LDPC encoder 150, a parity permutation unit 160, a parity puncturing
unit 170,
a zero removing unit 180, a bit interleaving unit 190, and a constellation
mapping unit
195.
[0046] The signaling information encoding apparatus 100 shown in FIG. 1 may
be viewed as corresponding to a Bit-Interleaved Coded Modulation (BICM)
apparatus.
In this case, the error correction encoder of the B1CM apparatus may be viewed
as
corresponding to the segmentation unit 110, the scrambling unit 120, the BCH
encoder
130, the zero padding unit 140, the LDPC encoder 150, the parity permutation
unit 160,
the parity puncturing unit 170, and the zero removing unit 180 that are shown
in FIG. 1.
[0047] When the length of the signaling information is longer than a preset
length, the segmentation unit 110 segments the signaling information into a
plurality of
groups in order to segment the signaling information into a plurality of LDPC
codewords and then transmit the LDPC codewords. That is, when the signaling
information cannot be contained in a single LDPC codeword, the segmentation
unit may
determine the number of codewords in which the signaling information is to be
contained, and then may segment the signaling information according to the
determined
number of codewords.
[0048] For example, when the length of the signaling information is fixed
like
L 1 -Basic, the signaling information encoding apparatus 100 may not include
the
segmentation unit 110.
[0049] For example, when the length of the signaling information is
variable like
Li-Detail, the signaling information encoding apparatus 100 may include the
segmentation unit 110.
[0050] The scrambling unit 120 performs scrambling in order to protect the
signaling information. In this case, the scrambling may be performed using
various
methods that are known in the present technical field.
[0051] The BCH encoder 130 performs BCH encoding using a BCH parity
whose parity length N b ch _panty is 168 bits.
[0052] In this case, the BCH encoding may be the same as BCH encoding for
LDPC code in which the length of data BICM is 16200.
6
CA 02977629 2017-08-23
[0053] In this case, a BCH polynomial used for the BCH encoding may be
expressed in Table 1 below, and the BCH encoding expressed in Table 1 may have
12-
bit error correction capability:
Table 1
Code Length Nidp, =16200
g1(x) +x+x3+xs1_x I 4
g2(X) +x6+x8+xl 1+x'4
g3(x) 1 +x+x2+x6+xq+x 1(4)(14
g4(X) 1 +x4 x7+x8+x10+x12+x14
g5(x) +x2+x4+x6 x8 x9+x1I+xl3+x14
g6(X) 1-f x3+x7+x8+x9 x13 x1 4
g7(x) +x2+x5_0(6 x7+x1 04-x11+ x13+x14
g8(x) x5+x8+x9+x10 x1 I +x14
g9(X) 1+x+x2+x3+x4x10+x 14
g10(X) 1 +x3+x6+x9+x11+ x12+x14
g 11 (X) x4+xl 1+xl 2+x14
g12(X) +X+X2-1-X3+X5 X6 X7+X8 X I 0 X13+X14
[0054] After the BCH encoding has been performed, the zero padding unit 140
performs zero padding or shortening.
[0055] In this case, the zero padding means that part of a bit string is
filled with
bit "0."
[0056] As a result of the BCH encoding, the length of the bit string may be
expressed by N bch= Ksig N bch Panty = In this case, K,,g may be the number of
information bits of the BCH encoding. For example, when K,,g is fixed to 200
bits,
N bch may be 368 bits.
[0057] When the LDPC encoder 150 uses an LDPC code whose code rate is 3/15
and whose length is 16200, the information length Icy, of the LDPC code is
3240 bits.
In this case, since information that is to be actually transmitted is Nbch
bits and the
length of the information part of the LDPC code is Kidp, bits, zero padding,
i.e., the
process of filling bits corresponding to Kidpe-N,,õ with bit "0," is
performed.
[0058] In this case, the order of the zero padding plays an important role
in
determining the performance of the encoder, and the order of the zero padding
may be
expressed as shortening pattern order.
7
CA 02977629 2017-08-23
[0059] In this
case, the bits padded with zeros are used only for LDPC encoding,
and are not actually transmitted.
[0060] The LDPC
information bits composed of lcdp, bits is segmented into
groups, as shown in Equation 1 below. For example, when Kidpc is 3240,
r trafo_group
is 9, and thus the LDPC information bits may be grouped into 9 groups.
'Infogroup
[0061] Zi={i 360 360 x(j+1)}
for() ...j<N fo_group (1)
where Z is a group composed of 360 bits.
[0062] The part of
Kidp, bits that is zero-padded is determined according to the
following procedure.
[0063] (Step 1)
First, the number of groups in which all the bits thereof will be
padded with "0" is calculated using Equation 2 below:
[Kld Nbch
Npad= Pc (2)
360
[0064] For example,
when Kup, is 3240 and N bch is 368, Npad may be 7.
The fact that Npad is 7 indicates that the number of groups in which all the
bits thereof
will be padded with "0" is 7.
[0065] (Step 2)
When Npad is not 0, zero padding is performed on Npad
groups in the order of Zõ,(0),Z,,(,),...,Zõ.,(_1) according to the shortening
pattern
order 7r3(j) of Table 2 below. In this case, ;7-JP may refer to the shortening
pattern order of a j -th bit group.
[0066] When Npad is 0, the above
procedure is omitted.
Table 2
7rs(i) (0 < Nõoup)
MODE N group
s (0) 7r3(1) 7r,(2) n-3(3) 2r(4) zs(5)
7r(6) 7r,(7) rr(8)
Li- 7 8 5 4 1 2 6 3 0
Detail
[0067] The
shortening pattern order of Table 2 above indicates that zero padding
targets are selected in the order of an 8th group indexed as 7, a 9th group
indexed as 8, a
6th group indexed as 5, a 5th group indexed as 4, a 2nd group indexed as 1, a
3rd group
indexed as 2, a 7th group indexed as 6, a 4th group indexed as 3, and a first
group
indexed as 0. That is, when only 7 groups are selected as zero padding targets
in the
8
CA 02977629 2017-08-23
example of Table 2 above, a total of 7 groups, i.e., the 8th group indexed as
7, the 9th
group indexed as 8, the 6th group indexed as 5, the 5th group indexed as 4,
the 2nd
group indexed as 1, the 3rd group indexed as 2, and the 7th group indexed as
6, are
selected as the zero padding targets.
[0068] In particular, the shortening pattern order of Table 2 above may be
optimized for variable length signaling information.
[0069] When the number of groups in which all the bits thereof will be
padded
with "0" and the corresponding groups are determined, all the bits of the
determined
groups are filled with "0."
[0070] (Step 3) Additionally, for a group corresponding to 4s(Npa,), bits
corresponding to ( Kidp, - N bch - 360 x Npad ) from the start of the group
are
additionally zero-padded. In this case, the fact that zero padding is
performed from the
start of the corresponding group may indicate that zero padding is performed
from a bit
corresponding to a smaller index.
[0071] (Step 4) After the zero padding has been all completed, an LDPC
information bit string is generated by sequentially mapping BCH-encoded N bch
bits to
a remaining part that has not been zero-padded.
[0072] The LDPC encoder 150 performs LDPC encoding using K idpc and which
has been zero-padded and to which signaling information has been mapped.
[0073] In this case, the LDPC encoder 150 may correspond to an LDPC
codeword whose code rate is 3/15 and whose length is 16200. The LDPC codeword
is
a systematic code, and the LDPC encoder 150 generates an output vector, such
as that of
Equation 3 below:
A = (co, (ivii,"=94c-i,P0,P15===,P16200-K-1) (3)
[0074] For example, when K is 3240, parity bits may be 12960 bits.
[0075] The parity permutation unit 160 performs group-wise parity
interleaving
on a parity part, not an information part, as a preliminary task for parity
puncturing.
[0076] In this case, the parity permutation unit 160 may perform parity
interleaving using Equation 4 below:
Y1=X1, 0 j<K dõ /360
(4)
Y,= X,(,), K idõ /360 j<45
9
CA 02977629 2017-08-23
=
where is a j -
th group-wise interleaved bit group, and g(j) is the order of group-
wise interleaving, which may be defined in Table 3 below:
Table 3
Order of Group-wise interleaving
7i-(j) (9 j < 45)
Mode Ngroup ___________________________________________________
9 10 11 12 13 14 15 16 17 18
19 20
21 22 23 24 25 26 27 28 29 30 31 32
33 34 35 36 37 38 39 40 41 42 43 44
16 22 27 30 37 44 20 23 25 32 38 41
Ll-
45 9 10 17 18 21 33 35 14 28 12
15 19
Detail
11 24 29 34 36 13 40 43 31 26 39 42
[0077] That
is, the parity permutation unit 160 outputs 3240 bits (9 bit groups)
corresponding to information bits among the 16200 bits (45 bit groups) of the
LDPC
codeword without change, groups 12960 parity bits into 36 bit groups each
including
360 bits, and interleave the 36 bit groups in the order of group-wise
interleaving
corresponding to Table 3 above.
[0078] The
order of group-wise interleaving of Table 3 indicates that a 17th
group indexed as 16 is located at a 10th group location indexed as 9, a 23rd
group
indexed as 22 is located at a list group location indexed as 10, a 28th group
indexed as
27 is located at a 12nd group location indexed as 11,..., and a 43rd bit group
indexed as
42 is located at a 45th group location indexed as 44.
[0079] In this
case, the bit group (the bit group indexed as 16) at a front location
may correspond to most important parity bits, and the bit group (the bit group
indexed as
42) at a rear location may correspond to least important parity bits.
[0080] In
particular, the order of group-wise interleaving of Table 3 may be
optimized for variable length signaling information.
[0081] After
the parity interleaving (parity permutation) has been completed, the
parity puncturing unit 170 may puncture the partial parities of the LDPC
codeword.
The punctured bits are not transmitted. In this case, after the parity
interleaving has
been completed, parity repetition in which part of the parity-interleaved LDPC
parity
bits is repeated may be performed before parity puncturing is performed.
[0082] The
parity puncturing unit 170 calculates a final puncturing size, and
punctures bits corresponding to the calculated final puncturing size. The
final
puncturing size corresponding to the number of bits to be punctured may be
calculated
according to the length Nbd, of the BCH-encoded bit string as follows:
CA 02977629 2017-08-23
[0083] (Step 1) A temporary puncturing size N punc_temp is calculated using
Equation 5 below:
Npu n c_ temp =[-2An x (1c,pc ¨ Nbch)i+ B (5)
where k is the length of the LDPC information bit string, N to, is the length
of the
BCH-encoded bit string, A is a first integer, and B is a second integer.
[0084] In this case, the difference Kidpc¨ Nbch between the length of the
LDPC
information bit string and the length of the BCH-encoded bit string may
correspond to a
zero padding length or a shortening length.
[0085] The parameters for puncturing required for the calculation of
Equation 5
may be defined as in Table 4 below:
Table 4
N bch Kldpc A B n Nldpc_ partly 17M0D
Ll-
368-2520 3240 7 0 1 12960 2
Detail
where N idpc parity is the number of parity bits of the LDPC codeword, and
rimoD is a
modulation order. In this case, the modulation order may be 2, which is
indicative of
QPSK.
[0086] In particular, the parameters for puncturing of Table 4 may be
optimized
for variable length signaling information.
[0087] (Step 2) The temporary number of transmission bits N __ _temp is
calculated using the calculated temporary puncturing size N panc_tenv and N
idp,_ parity of
Table 4, as shown in Equation 6 below:
¨ NFFC temp = Nbch + Nldpc N_ parity punc_temm
(6)
[0088] (Step 3) The number of transmission bits N õ, is calculated using
the
temporary number of transmission bits N , as shown in Equation 7 below:
N (7) MC _temp x
PIC D
17WD
100891 The number of transmission bits NFFc is the sum of the length of the
information part and the length of the parity part after the completion of the
puncturing.
11
CA 02977629 2017-08-23
[0090] (Step 4) A final puncturing size N is calculated
using the calculated
number of transmission bits NF as shown in Equation 8 below:
N punc= N punc_tenp (NFEC N FEC _temp) (8)
where the final puncturing size Npun, is the size of parities that need to be
punctured.
[0091] That is, the
parity puncturing unit 170 may puncture the last N I,. bits of
the whole LDPC codeword on which the parity permutation and the repetition
have been
performed.
[0092] The zero
removing unit 180 removes zero-padded bits from the
information part of the LDPC codeword.
[0093] The bit
interleaving unit 190 performs bit interleaving on the zero-
removed LDPC codeword. In this case, the bit interleaving may be performed
using a
method in which the direction in which the LDPC codeword is recorded in memory
of a
preset size and the direction in which the LDPC codeword is read therefrom are
made
different.
[0094] The
constellation mapping unit 195 performs symbol mapping. For
example, the constellation mapping unit 195 may be implemented using a QPSK
method.
[0095] The signaling
information decoding apparatus 300 demodulates and
channel-decodes signaling information, such as Li-Basic, Li-Detail, or the
like.
[0096] The signaling
information decoding apparatus 300 includes a constellation
de-mapping unit 395, a bit de-interleaving unit 390, an inverse zero removing
unit 380,
an inverse parity puncturing unit 370, an inverse parity permutation unit 360,
an LDPC
decoder 360, an inverse zero padding unit 340, a BCH decoder 330, an inverse
scrambling unit 320, and an inverse segmentation unit 310.
[0097] The signaling
information decoding apparatus 300 shown in FIG. 1 may
be viewed as corresponding to a Bit-Interleaved Coded Modulation (BICM)
decoding
apparatus. In this case, the error correction decoder of the BICM decoding
apparatus
may be viewed as corresponding to the inverse zero removing unit 380, the
inverse
parity puncturing unit 370, the inverse parity permutation unit 360, the LDPC
decoder
360, the inverse zero padding unit 340, the BCH decoder 330, the inverse
scrambling
unit 320 and the inverse segmentation unit 310 that are shown in FIG. 1.
[0098] The inverse
segmentation unit 310 performs the inverse operation of the
segmentation unit 110.
12
CA 02977629 2017-08-23
=
[0099] The inverse scrambling unit 320 performs the inverse
operation of the
scrambling unit 120.
[00100] The BCH decoder 330 performs the inverse operation of the
BCH encoder
130.
[00101] The inverse zero padding unit 340 performs the inverse
operation of the
zero padding unit 140.
[00102] In particular, the inverse zero padding unit 340 may
receive an LDPC
information bit string from the LDPC decoder 350, may select groups whose all
bits are
filled with 0 using shortening pattern order, and may generate a BCH-encoded
bit string
from the LDPC information bit string using groups exclusive of the former
groups.
[00103] The LDPC decoder 350 performs the inverse operation of
the LDPC
encoder 150.
[00104] The inverse parity permutation unit 360 performs the
inverse operation of
the parity permutation unit 160.
[00105] In particular, the inverse parity permutation unit 360
may segment the
parity bits of the LDPC codeword into a plurality of groups, and may group-
wise de-
interleave the groups using the order of group-wise interleaving, thereby
generating an
LDPC codeword that is to be LDPC-decoded.
[00106] The inverse parity puncturing unit 370 performs the
inverse operation of
the parity puncturing unit 170.
[00107] In this case, the inverse parity puncturing unit 370 may
calculate a
temporary puncturing size using a first integer, multiplied by the difference
between the
length of the LDPC information bit string and the length of the BCH-encoded
bit string,
and a second integer different from the first integer, may calculate the
temporary number
of transmission bits using the difference between the sum of the length of the
BCH-
encoded bit string and 12960 and the temporary puncturing size, may calculate
the
number of transmission bits using the temporary number of transmission bits
and
modulation order, may calculate a final puncturing size using the temporary
number of
transmission bits, the number of transmission bits and the temporary number of
transmission bits, and may generate an LDPC codeword to be provided to the
inverse
parity permutation unit 360 by taking into account the final puncturing size.
[00108] The inverse zero removing unit 380 performs the inverse
operation of the
zero removing unit 180.
[00109] The bit de-interleaving unit 390 performs the inverse
operation of the bit
interleaving unit 190.
13
CA 02977629 2017-08-23
=
[001101 The constellation de-mapping unit 395 performs the
inverse operation of
the constellation mapping unit 195.
[00111] FIG. 2 is an operation flowchart showing a signaling
information
encoding method according to an embodiment of the present invention.
[00112] Referring to FIG. 2, the signaling information encoding
method according
to the embodiment of the present invention includes segmenting signaling
information
into a plurality of groups first at step S210.
[00113] At step S210, when the length of the signaling
information is longer than
a preset length, the signaling information is segmented into a plurality of
groups in order
to segment the signaling information into a plurality of LDPC codewords and
then
transmit the LDPC codewords. That is, when the signaling information cannot be
contained in a single LDPC codeword, the number of codewords in which the
signaling
information is to be contained may be determined and then the signaling
information
may be segmented according to the determined number of codewords at step 5210.
[00114] For example, when the length of the signaling information
is variable like
Li-Detail, the signaling information encoding method may include step S210.
[00115] For example, when the length of the signaling information
is fixed like
Ll-Basic, the signaling information encoding method may not include step S210.
[00116] Furthermore, the signaling information encoding method
according to the
embodiment of the present invention includes performing scrambling in order to
protect
the signaling information at step S220.
[00117] In this case, the scrambling may be performed using
various methods that
are known in the present technical field.
[00118] Furthermore, the signaling information encoding method
according to the
embodiment of the present invention includes performing BCH encoding using a
BCH
parity whose parity length NbaLpõ,,, is 168 bits at step S230.
[00119] Step S230 may be performed by the BCH encoder 130 shown
in FIG. 1.
[00120] Furthermore, the signaling information encoding method
according to the
embodiment of the present invention includes performing zero padding or
shortening
after the BCH encoding has been performed at step S240.
[00121] In this case, the zero padding may be performed by the
zero padding unit
140 shown in FIG. 1.
[00122] Since information that is to be actually transmitted is
Nbai bits and the
length of the information part of the LDPC code is Kup, bits, zero padding,
i.e., the
CA 02977629 2017-08-23
=
process of filling bits corresponding to Kap,- N bch with bit "0," is
performed at step
S240.
1001231 The zero padding of step S240 may be performed according to the
shortening pattern order of Table 2.
1001241 Furthermore, the signaling information encoding method according to
the
embodiment of the present invention includes performing LDPC encoding using
Kup,
and which has been zero-padded and to which signaling information has been
mapped at
step S250.
[00125] In this case, step S250 may be performed by an LDPC encoder
corresponding to an LDPC codeword whose code rate is 3/15 and whose length is
16200.
[00126] Furthermore, the signaling information encoding method according to
the
embodiment of the present invention includes performing group-wise parity
interleaving
on a parity part, not an information part, as a preliminary task for parity
puncturing at
step S260.
[00127] In this case, at step S260, the group-wise parity interleaving may
be
performed according to the order of group-wise interleaving of Equation 4 and
Table 3.
[00128] Furthermore, the signaling information encoding method according to
the
embodiment of the present invention includes puncturing the partial parities
of the
LDPC codeword after the parity interleaving (parity permutation) has been
completed at
step S270.
[00129] At step S270, the punctured bits are not transmitted.
[00130] In this case, after the parity interleaving has been completed,
parity
repetition in which part of the parity-interleaved LDPC parity bits is
repeated may be
performed before parity puncturing is performed.
[00131] The parity puncturing of step S270 may be performed by the parity
puncturing unit 170 shown in FIG. 1.
[00132] Furthermore, the signaling information encoding method according to
the
embodiment of the present invention includes performing zero removing, i.e.,
the
process of removing the zero-padded bits from the information part of the LDPC
codeword, at step S280.
[00133] Furthermore, the signaling information encoding method according to
the
embodiment of the present invention includes performing bit interleaving on
the zero-
removed LDPC codeword at step S290. In this case, step S290 may be performed
CA 02977629 2017-08-23
using a method in which the direction in which the LDPC codeword is recorded
in
memory of a preset size and the direction in which the LDPC codeword is read
therefrom are made different.
[00134] Furthermore, the signaling information encoding method according to
the
embodiment of the present invention includes performing symbol mapping at step
S295.
[00135] FIG. 3 is an operation flowchart showing a signaling information
decoding method according to an embodiment of the present invention.
[00136] Referring to FIG. 3, the signaling information decoding method
according
to the embodiment of the present invention includes performing constellation
de-
mapping on a signal received via an antenna at step S310.
[00137] In this case, step S310 may correspond to the inverse operation of
step
S295 shown in FIG. 2, and may be performed by the constellation de-mapping
unit 395
shown in FIG. 1.
[00138] Furthermore, the signaling information decoding method according to
the
embodiment of the present invention includes performing bit de-interleaving at
step
S320.
[00139] In this case, step S320 may correspond to the inverse operation of
step
S290 shown in FIG. 2, and may be performed by the bit de-interleaving unit 390
shown
in FIG. I.
[00140] Furthermore, the signaling information decoding method according to
the
embodiment of the present invention includes performing inverse zero removing
at step
S330.
[00141] In this case, step S330 may correspond to the inverse operation of
step
S280 shown in FIG. 2, and may be performed by the inverse zero removing unit
380
shown in FIG. 1.
[00142] Furthermore, the signaling information decoding method according to
the
embodiment of the present invention includes performing inverse parity
puncturing at
step S340.
[00143] In this case, step S340 may correspond to the inverse operation of
step
S270 shown in FIG. 2, and may be performed by the inverse parity puncturing
unit 370
shown in FIG. I.
[00144] Furthermore, the signaling information decoding method according to
the
embodiment of the present invention includes performing inverse parity
permutation at
step S350.
16
CA 02977629 2017-08-23
[00145] In this case, step S350 may correspond to the inverse operation of
step
S260 shown in FIG. 2, and may be performed by the inverse parity permutation
unit 360
shown in FIG. 1.
[00146] Furthermore, the signaling information decoding method according to
the
embodiment of the present invention includes performing LDPC decoding at step
S360.
[00147] In this case, step S360 may correspond to the inverse operation of
step
S250 shown in FIG. 2, and may be performed by the LDPC decoder 350 shown in
FIG.
1.
[00148] Furthermore, the signaling information decoding method according to
the
embodiment of the present invention includes performing inverse zero padding
at step
S370.
[00149] In this case, step S370 may correspond to the inverse operation of
step
S240 shown in FIG. 2, and may be performed by the inverse zero padding unit
340
shown in FIG. I.
[00150] Furthermore, the signaling information decoding method according to
the
embodiment of the present invention includes performing BCH decoding at step
S380.
[00151] In this case. step S380 may correspond to the inverse operation of
step
S230 shown in FIG. 2, and may be performed by the BCH decoder 330 shown FIG.
1.
[00152] Furthermore, the signaling information decoding method according to
the
embodiment of the present invention includes performing inverse scrambling at
step
S390.
[00153] In this case, step S390 may correspond to the inverse operation of
step
S220 shown in FIG. 2, and may be performed by the inverse scrambling unit 320
shown
in FIG. I.
[00154] Furthermore, the signaling information decoding method according to
the
embodiment of the present invention includes performing inverse segmentation
at step
S395.
[00155] In this case, step S395 may correspond to the inverse operation of
step
S210 shown in FIG. 2, and may be performed by the inverse segmentation unit
310
shown in FIG. I.
[00156] FIG. 4 is a diagram showing a broadcast signal frame according to
an
embodiment of the present invention.
[00157] Referring to FIG. 4, the broadcast signal frame according to the
embodiment of the present invention may include a bootstrap 421, a preamble
423, and
data symbols 425.
17
CA 02977629 2017-08-23
[00158] The preamble 423 includes signaling information.
[00159] In an example shown in FIG. 4, the preamble 423 may include Li-
Basic
information 431 and Li -Detail information 433.
[00160] In this case, the LI-Basic information 431 may be fixed-length
signaling
information.
[00161] For example, the Li-Basic information 431 may correspond to 200
bits.
[00162] In this case, the LI-Detail information 433 may be variable length
signaling information.
[00163] For example, the Li-Detail information 433 may correspond to 200 to
2352 bits.
[00164] An LDPC (low-density parity check) code is known as a code very
close
to the Shannon limit for an additive white Gaussian noise (AWGN) channel, and
has the
advantages of asymptotically excellent performance and parallelizable decoding
compared to a turbo code.
[00165] Generally, an LDPC code is defined by a low-density parity check
matrix
(PCM) that is randomly generated. However, a randomly generated LDPC code
requires a large amount of memory to store a PCM, and requires a lot of time
to access
memory. In order to overcome these problems, a quasi-cyclic LDPC (QC-LDPC)
code
has been proposed. A QC-LDPC code that is composed of a zero matrix or a
circulant
permutation matrix (CPM) is defined by a PCM that is expressed by the
following
Equation 9:
Jail
jc121 fall j02.
H = , for agE (0,1,..., L ¨1, oo} (9)
ram, ja, raõ,,
_
[00166] In this equation, J is a CPM having a size of L x L , and is given
as
Equation 10 below. In the following description, L may be 360.
0 1 0 = = = 0
001...0
iLxL = : : : = : (10)
0 0 0 = = = 1
1 0 0 =- = 0
[00167] Furthermore, J' is obtained by shifting an Lx L identity matrix
I (.1 ) to the right i (0 i< L) times, and .r is an Lx L zero matrix.
18
CA 02977629 2017-08-23
=
Accordingly, in the case of a QC-LDPC code, it is sufficient if only index
exponent i
is stored in order to store J', and thus the amount of memory required to
store a PCM is
considerably reduced.
[00168] FIG. 5
is a diagram showing the structure of a PCM corresponding to an
LDPC code according to an embodiment of the present invention.
[00169]
Referring to FIG. 5, the sizes of matrices A and C are g x K and (N-K-g)
x (K+g), respectively, and are composed of an Lx L zero matrix and a CPM,
respectively. Furthermore, matrix Z is a zero matrix having a size of g x (N-K-
g),
matrix D is an identity matrix having a size of (N-K-g) x (N-K-g), and matrix
B is a dual
diagonal matrix having a size of g x g. In this case, the matrix B may be a
matrix in
which all elements except elements along a diagonal line and neighboring
elements
below the diagonal line are 0, and may be defined as Equation 11 below:
/LxL 0 0 = = = 0 0 0
1 LxL 1LxL 0 = = = 0 0 0
0 ILxL ILxL == 0 0 0
Bgxg (11)
. .
0 0 0 ' = ' LxL 11,x1
0 0 0 = = = 0 ILxL ILxL _
where /LõL is an identity matrix having a size of L x L.
[00170] That
is, the matrix B may be a bit-wise dual diagonal matrix, or may be a
block-wise dual diagonal matrix having identity matrices as its blocks, as
indicated by
Equation 11 above. The bit-wise dual diagonal matrix is disclosed in detail in
Korean
Patent Application Publication No. 2007-0058438, etc.
[00171] In
particular, it will be apparent to those skilled in the art that when the
matrix B is a bit-wise dual diagonal matrix, it is possible to perform
conversion into a
Quasi-cyclic form by applying row or column permutation to a PCM including the
matrix B and having a structure shown in FIG. 5.
[00172] In this
case, N is the length of a codeword, and K is the length of
information.
[00173] The
present invention proposes a newly designed QC-LDPC code whose
code rate is 3/15 and whose codeword length is 16200, as shown in Table 5
below.
That is, the present invention proposes an LDPC code that is designed to
receive
information having a length of 3240 and generate an LDPC codeword having a
length of
16200.
19
CA 02977629 2017-08-23
=
=
[00174] Table 5 shows the sizes of the matrices A, B, C, D and Z
of the QC-LDPC
code according to the present invention:
Table 5
Sizes
Code rate Length
A
11880x 11880x 1080x
3/15 16200 1080 x 3240 1080x 1080
4320 11880 11880
[00175] The newly designed LDPC code may be represented in the
form of a
sequence, an equivalent relationship is established between the sequence and
the matrix
(parity bit check matrix), and the sequence may be represented as shown the
following
table:
[Table]
1st row: 8 372 841 4522 5253 7430 8542 9822 10550 11896 11988
2nd row: 80 255 667 1511 3549 5239 5422 5497 7157 7854 11267
3rd row: 257 406 792 2916 3072 3214 3638 4090 8175 8892 9003
4th row: 80 150 346 1883 6838 7818 9482 10366 10514 11468 12341
5th row: 32 100 978 3493 6751 7787 8496 10170 10318 10451 12561
6th row: 504 803 856 2048 6775 7631 8110 8221 8371 9443 10990
7th row: 152 283 696 1164 4514 4649 7260 7370 11925 11986 12092
8th row: 127 1034 1044 1842 3184 3397 5931 7577 11898 12339 12689
9th row: 107 513 979 3934 4374 4658 7286 7809 8830 10804 10893
10th row: 2045 2499 7197 8887 9420 9922 10132 10540 10816 11876
list row: 2932 6241 7136 7835 8541 9403 9817 11679 12377 12810
12nd row: 2211 2288 3937 4310 5952 6597 9692 10445 11064 11272
[00176] An LDPC code that is represented in the form of a
sequence is being
widely used in the DVB standard.
[00177] According to an embodiment of the present invention, an
LDPC code
presented in the form of a sequence is encoded, as follows. It is assumed that
there is
an information block S =
K_1) having an information size K. The LDPC
encoder generates a codeword A= (AO,
having a size of
N= K-F Al1 M, using the information block S having a size K. In this case,
Mi=g, and M2= N¨K¨g . Furthermore, M, is the size of a parity corresponding
to the dual diagonal matrix B, and M, is the size of a parity corresponding to
the
identity matrix D. The encoding process is performed as follows:
[00178] - Initialization:
CA 02977629 2017-08-23
=
=
/11 S, for i 0,1,...,K ¨ 1
(12)
pi = 0 for j = 0,1,...,4 + M2 -
[00179] - First
information bit A, is accumulated at parity bit addresses specified
in the 1st row of the sequence of the above table. For example, in an LDPC
code
whose length is 16200 and whose code rate is 3/15, an accumulation process is
as
follows:
Ps = P8 lEb /10 P372 = P372 20 P841 = P841 AO P4522 = P4522 (3) AO P5253 =
P5253
P7430 - P7430 AD P8542 - P8542 20 P9822 - P9822 20 P10550 - P10550 (+) /10
P11896= P11896(1)20 P11988=P11988(1)20
where the addition ED occurs in GF(2).
[00180] - The subsequent L-1
information bits, i.e., A.,n, = 1,2,...,L ¨1, are
accumulated at parity bit addresses that are calculated by the following
Equation 13:
(x + m x Q1) mod 4 if x < 4
(13)
+ {(x ¨ + mx Q2) mod M2} if x
where x denotes the addresses of parity bits corresponding to the first
information bit
, i.e., the addresses of the parity bits specified in the first row of the
sequence of
Table, Q, = M IL , 2= M2 IL, and L = 360 . Furthermore, Q1 and Q2 are
defined in the following Table 2. For example, for an LDPC code whose length
is
16200 and whose code rate is 3/15, 4 =1080 ,Q1=3, M2 = 11880 , Q2 = 33 and
L = 360, and the following operations are performed on the second bit using
Equation 13 above:
P1 1 Pi0 Al P375 = P375 e Al P844 = P844 Al P4555 '--- P4555 Al P5286 =
P52869 Al
P7463 = P7463 Al P8575 = P8575 21 P9855 P9855 Al p10583= P10583 21
P11929 = P11929 21 P12021= P12021 21
[00181] Table 6
shows the sizes of M,, Qõ M2 and Q2 of the designed QC-
LDPC code:
Table 6
Sizes
Code rate ________________________________________________ Length
M2 Ql Q2
3/15 16200 1080 11880 3 33
21
CA 02977629 2017-08-23
[00182] - The
addresses of parity bit accumulators for new 360 information bits
ranging from A, to .12,, are calculated and accumulated from Equation 13 using
the
second row of the sequence.
[00183] - In a
similar manner, for all groups composed of new L information
bits, the addresses of parity bit accumulators are calculated and accumulated
from
Equation 13 using new rows of the sequence.
[00184] - After all the information bits ranging from to AK-1 have
been
exhausted, the operations of Equation 14 below are sequentially performed from
i =1:
p,= p, e for i = 0,1,..., MI ¨1 (14)
[00185] - Thereafter,
when a parity interleaving operation, such as that of Equation
15 below, is performed, parity bits corresponding to the dual diagonal matrix
B are
generated:
117C+L=r+s = PQrs t for 0 s < L, 0..t<Q1 (15)
[00186] When the
parity bits corresponding to the dual diagonal matrix B have
been generated using K information bits A., A.
i9===94-1, parity bits corresponding to the
identity matrix D are generated using the M1 generated parity bits 2K.
[00187] - For all groups composed of L information bits ranging from to
ic+m, -19 the addresses of parity bit accumulators are calculated using the
new rows
(starting with a row immediately subsequent to the last row used when the
parity bits
corresponding to the dual diagonal matrix B have been generated) of the
sequence and
Equation 13, and related operations are performed.
[00188] - When a
parity interleaving operation, such as that of Equation 16 below,
is performed after all the bits ranging from A.K to /1 have been
exhausted, a
parity corresponding to the identity matrix D is generated:
21C+M1+L=t+s = PA,10-Q2.s+t for 0 s < L, 0 t <Q, (16)
[00189] FIG. 6 is a
diagram showing an example of the operation of the zero
padding unit shown in FIG. 1.
[00190] Referring to
FIG. 6, a zero padding operation in the case where the
shortening pattern order is [4 1 5 2 8 6 0 7 3] can be seen.
[00191] In the
example shown in FIG. 6, the length of the LDPC information bit
string is 3240, and thus LDPC information bits include 9 groups each composed
of 360
bits.
22
CA 02977629 2017-08-23
=
[00192] First, when the number of groups for which all the bits
thereof are filled
with 0 is determined using Equation 2, (3240-368/360) = 7.9, and thus 7 groups
are
determined to be the groups for which all the bits thereof are filled with 0.
[00193] Furthermore, since the shortening pattern order is [4 1 5 2 8
6 0 7 3], a
total of 7 groups, i.e., a 5th group 610 indexed as 4, a 2nd group 620 indexed
as 1, a 6th
group 630 indexed as 5, a 3rd group 640 indexed as 2, a 9th group 650 indexed
as 8, a
7th group 660 indexed as 6 and a 1st group 670 indexed as 0, are selected, and
all the
bits of the groups are filled with 0.
[00194] Furthermore, since an 8th group 680 indexed as 7 is next to
the 1st group
670 indexed as 0, 352 (= 3240 ¨ 368 ¨ (360 x 7)) bits from the beginning of
the 8th
group 680 indexed as 7 are filled with 0.
[00195] After the zero padding has been completed, the BCH-encoded bit
string of
NhCh (-368) bits is sequentially mapped to a total of 368 bits, i.e., the 360
bits of the 4th
group 690 indexed as 3 and the remaining 8 bits of the 8th group 680 indexed
as 7.
[00196] FIG. 7 is a diagram showing an example of the operation of the
parity
permutation unit shown in FIG. 1.
[00197] Referring to FIG. 7, a parity permutation operation in the
case where the
order of group-wise interleaving corresponding to the sequence [20 23 25 32 38
41 18 9
11 31 24 14 15 26 40 33 19 28 34 16 39 27 30 21 44 43 35 42 36 12 13 29 22 37
17]
can be seen.
[00198] Kidp, (=3240) information bits are not interleaved, and 36
groups each
composed of 360 bits (a total of 12960 bits) become an interleaving target.
[00199] Since the order of group-wise interleaving corresponds to the
sequence
[20 23 25 32 38 41 18 9 10 11 31 24 14 15 26 40 33 19 28 34 16 39 27 30 21 44
43 35
42 36 12 13 29 22 37 17], the parity permutation unit locates a 21st group
indexed as 20
at a 10th group location 710 indexed as 9, a 24th group indexed as 23 at a
11th group
location 720 indexed as 10, ..., a 38th group indexed as 37 at a 44th group
location 730
indexed as 43, and a 18th bit group indexed as 17 at a 45th group location 740
indexed
as 44.
1002001 The parity puncturing may be performed from the rear side of
the parity-
interleaved parity bits (from the end of the 18th bit group indexed as 17).
[00201] FIG. 8 is a diagram showing an example of the operation of the
zero
removing unit shown in FIG. 1.
23
CA 02977629 2017-08-23
[00202] Referring to FIG. 8, it can be seen that the zero removing unit
generates
signaling information for transmission by removing zero-padded parts from the
information part of an LDPC codeword.
[00203] FIG. 9 is a block diagram showing a parity puncturing apparatus
according to an embodiment of the present invention.
[00204] Referring to FIG. 9, the parity puncturing apparatus according to
the
embodiment of the present invention includes a processor 920, and memory 910.
[00205] The processor 920 punctures a number of bits corresponding to a
final
puncturing size from the rear side of a parity bit string for parity
puncturing for the
parity bits of an LDPC codeword whose length is 16200 and whose code rate is
3/15.
[00206] In this case, the LDPC codeword may include zero-padded variable
length
signaling information as information bits.
[00207] In this case, the final puncturing size may be calculated using a
temporary
puncturing size, the number of transmission bits and the temporary number of
transmission bits, as shown in Equation 8, the number of transmission bits may
be
calculated using the temporary number of transmission bits and modulation
order, as
shown in Equation 7, the temporary number of transmission bits may be
calculated using
the difference between the sum of the length of the BCH-encoded bit string and
12960
and the temporary puncturing size, as shown in Equation 6, and the temporary
puncturing size may be calculated using a value obtained by dividing the
difference
between the length of the LDPC information bit string and the length of the
BCH-
encoded bit string by 2, as shown in Equation 5.
[00208] In this case, the temporary puncturing size may be calculated using
a first
integer A, multiplied by a value obtained by dividing the difference between
the length
of the LDPC information bit string and the length of the BCH-encoded bit
string by 2,
and a second integer B different from the first integer, as shown in Equation
5.
[00209] In this case, as shown in Table 4 above, the first integer may be
7, the
second integer may be 0, and the modulation order may be 2 that corresponds to
QPSK.
[00210] The memory 910 provides a parity bit string for parity puncturing
for the
parity bits of an LDPC codeword whose length is 16200 and whose code rate is
3/15.
[00211] In this case, the parity bit string may be generated by segmenting
the
parity bits of the LDPC codeword into a plurality of groups and then group-
wise
interleaving the groups using the order of group-wise interleaving.
24
CA 02977629 2017-08-23
[00212] In this case, the order of group-wise interleaving may correspond
to the
sequence [16 22 27 30 37 44 20 23 25 32 38 41 910 17 18 21 33 35 14 28 12 15
19 11
24 29 34 36 13 40 43 31 26 3942].
[00213] The parity puncturing apparatus shown in FIG. 9 may correspond to
the
parity puncturing unit 170 shown in FIG. 1.
[00214] Furthermore, the structure shown in FIG. 9 may correspond to an
inverse
parity puncturing apparatus. In this case, the inverse parity puncturing
apparatus may
correspond to the inverse parity puncturing unit 370 shown in FIG. 1.
[00215] When the structure shown in FIG. 9 corresponds to the inverse
parity
puncturing apparatus, the processor 920 calculates a temporary puncturing size
using the
length of an LDPC information bit string and the length of a BCH-encoded bit
string,
calculates the temporary number of transmission bits using the difference
between the
sum of the length of the BCH-encoded bit string and 12960 and the temporary
puncturing size, calculates the number of transmission bits using the
temporary number
of transmission bits and modulation order, calculates a final puncturing size
using the
temporary number of transmission bits, the number of transmission bits and the
temporary number of transmission bits, and performs inverse parity puncturing
corresponding to the final puncturing size, thereby generating the parity bit
string of an
LDPC codeword whose length is 16200 and whose code rate is 3/15.
1002161 In this case, the LDPC codeword may include zero-padded variable
length
signaling information as information bits.
[00217] In this case, the temporary puncturing size may be calculated using
a
value obtained by dividing the difference between the length of the LDPC
information
bit string and the length of the BCH-encoded bit string by 2, as shown in
Equation 5.
[00218] In this case, the temporary puncturing size may be calculated using
a first
integer A, multiplied with a value obtained by dividing the difference between
the length
of the LDPC information bit string and the length of the BCH-encoded bit
string by 2,
and a second integer B different from the first integer, as shown in Equation
5.
[00219] In this case, as shown in Table 4, the first integer may be 7, the
second
integer may be 0, and the modulation order may be 2 that corresponds to QPSK.
[00220] The memory 910 stores the parity bit string.
[00221] FIG. 10 is an operation flowchart showing a parity puncturing
method
according to an embodiment of the present invention.
[00222] Referring to FIG. 10, the parity puncturing method according to the
embodiment of the present invention includes calculating a temporary
puncturing size
CA 02977629 2017-08-23
=
using the difference between the length of an LDPC information bit string and
the length
of a BCH-encoded bit string at step S1010.
[00223] In this case, the temporary puncturing size may be calculated
using a
value obtained by dividing the difference between the length of the LDPC
information
bit string and the length of the BCH-encoded bit string by 2, as shown in
Equation 5.
[00224] In this case, the temporary puncturing size may be calculated
using a first
integer A, multiplied by a value obtained by dividing the difference between
the length
of the LDPC information bit string and the length of the BCH-encoded bit
string by 2,
and a second integer B different from the first integer, as shown in Equation
5.
[00225] In this case, as shown in Table 4, the first integer may be 7,
the second
integer may be 0, and the modulation order modulation order may be 2 that
corresponds
to QPSK.
[00226] Furthermore, the parity puncturing method according to the
embodiment
of the present invention includes calculating the temporary number of
transmission bits
using the difference between the sum of the length of the BCH-encoded bit
string and
12960 and the temporary puncturing size at step S1020.
[00227] Furthermore, the parity puncturing method according to the
embodiment
of the present invention includes calculating the number of transmission bits
using the
temporary number of transmission bits and modulation order at step S1030.
[00228] Furthermore, the parity puncturing method according to the
embodiment
of the present invention includes calculating a final puncturing size using
the temporary
number of transmission bits, the number of transmission bits and the temporary
number
of transmission bits at step S1040.
[00229] Furthermore, the parity puncturing method according to the
embodiment
of the present invention includes puncturing the number of bits corresponding
to the
final puncturing size from the rear side of the parity bit string for parity
puncturing for
the parity bits of an LDPC codeword whose length is 16200 and whose code rate
is 3/15
at step S1050.
[00230] In this case, the LDPC codeword may include zero-padded
variable length
signaling information as information bits.
[00231] In this case, the parity bit string may be generated by
segmenting the
parity bits of the LDPC codeword into a plurality of groups and then group-
wise
interleaving the groups using the order of group-wise interleaving.
26
CA 02977629 2017-08-23
=
[00232] In this case, the order of group-wise interleaving may
correspond to the
sequence [16 22 27 30 37 44 20 23 25 32 38 41 9 10 17 18 21 33 35 14 28 12 15
19 11
24 29 34 36 13 40 43 31 26 39 42].
[00233] As described above, the parity puncturing apparatus, the
parity puncturing
method and the inverse parity puncturing apparatus according to the present
invention
are not limited to the configurations and methods of the above-described
embodiments,
but some or all of the embodiments may be selectively combined such that the
embodiments can be modified in various manners.
27
